Ringing from my guitar

I own an Epiphone les Paul junior with a semymour Duncan sh4-jb humbucker in it and a Marshall Code 50 amp. I’m trying to find a good avenged sevenfold tone for the amp and when I try the one on the Marshall Code patches page (preset/patch is called critical acclaim) and whenever I stop strumming or palm muting the strings and leave them open, the amp squeals. I know that it has something to do with the distortion effect I put on the amp. When I have the distortion turned up a lot, there is a lot of that squealing sound I talked about earlier. The settings are:
-bass:5, gain:8, mid:7.5, treble:6, vol:9.1
-ampd silver jubilee (gate:2.5),power amp: classic Marshall 100w(presence:8.5,resonance:5), cab:1960HW
-prefx: distortion(mode:dis, drive:1.5, tone:8, level:2.7)
If anyone has any advice on what I should do, please tell me.
And yes I know this is a very long forum

I’ll try adjusting these two things and see if it helps. Thanks!

Like 10 minutes after i wrote this post i figured out that I just had to increase the gate/threshold on the amp and just forgot to post it.